Electrodeposition of nickel



ELECTRODEPOSITION F NICKEL Henry Brown, Huntington Woods, and Richard 3. Cianss, Grosse Pointe Park, Mich., assignors to The Udylite Research Corporation, Detroit, Mich, a corporation of Michigan No Drawing. Application October 4, 1955, Serial No. 538,528

14 Claims. (Cl. 204-49) This invention relates to the electrodeposition of ductile, fine-grained, bright nickel from aqueous acidic nickel baths.

This object can be accomplished by the use in Watts type nickel baths or modifications thereof, of certain soluble unsaturated organic compounds exemplified in Table I, together with one or more of the organic sulfonompounds exemplified in Table II.

The unsaturated compounds of Table I consist of alkynoxy alkane carboxylic acids especially alkynoxy acetic, propionic, succinic, and propane tricarboxylic acids containing a total of from five to fifteen carbon atoms. The unsaturation of these compounds is due to the triple bonded carbon to carbon linkage (CEC), and the unsaturated linkage is separated from the carboxyl group by two to four inclusive carbon atoms and one intervening or intermediate oxygen atom linkage. The compounds of Table I can be characterized by the following grouping (A):

R=H, CH3, COOH, or CI-IzCOOH R1=H, or CH3 Rz=H, CH3, or Cal-I5 n=0 or 1 If the carboxylic group is in alpha position to the triple bond, that is, directly connected to the triple bonded carbon to carbon linkage, as in propiolic acid HCEC--CO0H or in acetylene dicarboxylic acid HOOCEC-CCOOH brightening only over a narrow current density range is obtained, and the low current density plate is dull and dark, and of poor ductility, when used in conjunction with the organic sulfon-compounds of Table II. This is where similar to a certain extent to the results with acrylic acid,

CH2=CH-COOH, and maleic acid HOOCC=C--COOH 2,800,441 Patented July 23, 1957 ly the brightness given by the most effective organic sulfon-compounds of Table II. If an linkage is present instead of .oxygen, the brightening produced by these unsaturated compounds is poor, ofiering little improvement over the brightness given by the sulfon-compounds of Table II. Thus, in certain respects and within certain compounds, the unsaturated -CC bond acts not only like the C=C- bond, but also like the unsaturated C=N- bond. For example, with pyridine, when the carboxylic group is attached in quaternary form, the compound N o( CHlC 0 on is an excellent brightener, whereas, the compound OOOH is a poor brightener, when used in conjunction with the organic sulfon-compounds of Table II.

The unsaturated compounds of Table I carrying the CEC bond with a carboxyl group separated from the triple bond by two to four carbon atoms and an in termediate or intervening oxygen atom, when used in conjunction with the compounds of Table II, not only make possible very bright ductile plate over a very wide current density range, but also are not very critical to causing misplating or dark plate in the low current density areas (recesses of articles).

The preferred alkane carboxylic acid groupings in the alkynoxy alkane carboxylic compounds of this invention are those with CH2 or -CH3 radical per carboxylic group such as in acetic acid (-CHzCOOH), succinic acid and propane tricarboxylic From the standpoint of low price and efiicacy in the baths the preferred compounds are the alkynoxy acetic acids such as Z-butynoxy-l, 4-diacetic acid, and 2-propynoxy-l-acetic acid. Alkynoxy alkane carboxylic acids in which the alkane group is greater than propane, as for example in butyric, valeric, and caprylic, etc. acids, are of limited solubility in the baths and also are of an oily or fatty nature and are not as desirable to use.

The unsaturated compounds of Table I give especially high brilliance and ductility when used in conjunction with about 0.1 to 1 gram per liter of allyl sulfonic acid, and a second organic sulfon-compound selected from benzene sulfonic acids, benzene sulfonamides and benzene sulfonimides or mixtures, the latter organic sulfoncompounds in a concentration of about 0.1 to 6 grams per liter.

The compounds of Table I can be used as the free acids gas pitting of the cathode without the use of surface active agents, and besides it greatly improves the brilliance of the plate, with and without air agitation. The faster the agitation of the solution or of the cathode, the less the concentration of the compounds of Table I that need to be employed to obtain high brilliance, also the brighter the plate at a given ductility. At the higher temperatures of the bath, the less the concentration of the compounds of Table I that need to be used to obtain bright plate at rapid rates of solution agitation. It is to be understood that the compounds of Tables I and II may be used in various combinations in baths of the general type illustrated below by employing the concentrations indicated in Tables I and II.

The cathode current densities to be used in the following examples average from about 10 to 200 amps./ sq. ft. depending mainly on the temperature, degree of solution agitation, and the composition of the bath. Higher temperatures and higher degrees of agitation permit higher current densities to be employed satisfactorily.

Example 1 g./1. NiSO4.6H2O 25-300 NiCl2.6H2O 225-30 H3BO 30-45 Propynoxy propionic acid (HCECCH20-C2H4COOH) at 0.01 to 0.12 g./l. Allyl sulfonic acid at 0.3 to 1.5 g./l. o-Benzoyl sulfimide at 0.1 to 2 g./l. pH=2.5 to 4.8, temp.=45 C. to 70 C.

Example 2 g./l. NiSO4.6H2O 150-300 NiCl2.6H2O 30-60 H3BO 30-40 Butynoxy-1,4-diacetic acid (HOOC-CH2OCH2-CECCH2-OCH2COOH) at 0.05 to 0.6 g./l. Allyl sulfonic acid at 0.5 to 1.5 g./l. o-Benzoyl sulfimide at 0.1 to 0.3 g./l. pH=2.5 to 4.5, temp.=45 C. to 80 C. (113 F.-

Example 3 g./1. NiCl2.6HzO 150 H3BO3 40-50 NaBF -3 Propynoxy acetic acid (HCECCII2OCH2COOH) at 0.005 to 0.08 g./l. Butynoxy-lA-diacetic acid C-CH2OCH2COOH) at 0.05 to 0.5 g./l.

g./l. Allyl sulfonic acid 0.5 to 1.5 o-Benzoyl sulfimide 0.5 to 3 pH=2.5 to 4.5, temp.=45 C. to 75 C.

Example 4 NiS04.6H2O 25-300 NiCl2.6H2O 225-30 B31303 30-45 Dimethyl propynoxy acetic acid CH3 (licao-i l-o-omooon) 6 at 0.01 to 0.12 gram per liter Allyl sulfonic acid at 0.3 to 1 g./l. o-Benzoyl sulfimide at 0.1 to 2 g./l. Benzene disulfonic acid at 2 to 6 g./l. pH=2.5 to 4.8, temp.=45 C. to C.

at 0.005 to 0.08 gram per liter ButynoXy-1,4-diacetic acid (HOOC-CH2OCH2-CEC-CH2OCH2COOH) at 0.03 to 0.3 g./l. Butyne-1,4-disulfonic acid (HO3SCH2CEC-CH2-SO3H) at 3-10 g./l. o-Benzoyl sulfimide at 0.1 to 2 g./l.

Benzene sulfonic acid at 2 to 6 g./l. pH=2.5 to 4.8, temp.=45 C. to 80 C.

Example 6 g./l. NiSO4.6H2O 25-300 NiCl2.6H2O 225-30 HsBOs 30-45 Propynoxy acetic acid (HCECCH20CH2COOH) at 0.005 to 0.12 g./l.

Allyl sulfonic acid at 0.1 to 1.5 g./l.

o-Sulfobenzaldehyde (forrnyl benzene sulfonic acid) at 0.5 to 4 g./l.

o-Benzoyl sulfimide at 0.05 to 3 g./l.

pH=2.5 to 5.2, temp.=45 C.-80 C.

Instead of nickel baths made up predominantly of nickel sulfate and nickel chloride, or mixtures of these salts, nickel fluoborate and nickel sulfamate may be used in whole or in part. Instead of boric acid, other butters such as nickel formate, succinate, citrate, etc., may be used, though in general boric acid is the preferred bufier as it allows the best leveling action. The best pH values for the baths are about 2.5 to 5.0, though pH'values from 2 to 6 at least, may be used. The bath temperatures may be from room to boiling, though in general the most convenient temperatures of operation are from about F. to F. Ammonium ions make the plate less ductile, but sodium, lithium, potassium or magnesium ions are not nearly as critical. The bromide ion may be present in high concentrations, but not the iodide ion as the latter in excessive concentration may cause a loss of cathode efficiency (from the free iodine formed by anodic oxidation of the iodide ion). Ferrous salts or cobalt salts or mixtures up to at least a concentration of forty grams per liter as sulphates, chlorides of fiuoborates may be present in the nickel bath, and yield nickel alloy plates containing as low as about sixty percent nickel and still the plate obtained is bright and ductile.

What is claimed:

1. A bath for electrodepositing bright nickel comprising an aqueous acidic solution of at least one nickel salt selected from the group consisting of nickel sulfate, nickel chloride, nickel fiuoborate and nickel sulfamate, said bath also containing dissolved therein about 0.005 to about 2 grams/liter of at least one alkynoxy alkane carboxylic acid having a total of 5 to 15 carbon atoms in which the unsaturated triple bonded carbon to carbon linkage is separated from the carboxyl group by 2 to 4 inclusive in which R is selected from the group consisting of hydrogen, methyl, carboxyl and carboxymethyl radicals, R is selected from the group consisting of hydrogen and methyl radicals,Rz'is selected from the group consisting of hydrogen, methyl and ethyl radicals, and n is not greater than 1 and in conjunction therewith about 0.1 gram/ liter to saturation of at least one brightener selected from the group consisting of benzene, diphenyl and naphthalene sulfonic acids, benzene sulfonamides and sulfonimides and di-benzene sulfonamides and sulfonimides and the halogenic, methyl, aldehydo derivatives of said sulfonic acids, sulfonamides and sulfonimides, and beta unsaturated alkene sulfonic acids having 4 to 2 carbon atoms. l

2. A bath for electrodepositing bright nickel comprising an aqueous acidic solution of at least one nickel salt selected from the group consisting of nickel sulfate, nickel chloride, nickel fluoborate and nickel sulfamate, said bath also containing dissolved therein 2-butynoxy-1,- 4-diacetic acid (HOOC-CH2OCH2 -CEC-CHz- O-CH2COOH) in a concentration of 0.01 to 0.6 grams/liter, and inconjunction therewith about 0.1 gram/ liter to saturation of at least one brightener selected from the group consisting of benzene, diphenyl and naphthalene sulfonic acids, benzene sulfonamides and sulfonimides and di-benzene sulfonamides and sulfonimides and the halogenic, methyl, aldehydo (formyl) derivatives of said sulfonic acids, sulfonamides and sulfonimides, and beta unsaturated alkene sulfonic acids having 4 to 2 carbon atoms.

3. A bath for electrodepositing bright nickel comprising an aqueous acidic solution of at least one nickel salt selected from the group consisting of nickel sulfate, nickel chloride, nickel fluoborate and nickel sulfamate, said bath also containing dissolved therein 2-propynoxyl-acetic acid (HCECCH2OCH2COOH) in a concentration of 0.005 to 0.15 grams/liter, and in conjunction therewith about 0.1 gram/liter to saturation of at least one brightener selected from the group consisting of benzene, diphenyl and naphthalene sulfonic acids, benzene sulfonamides and sulfonimides and dibenzene sulfonamides and sulfonimides and the halogenic, methyl, aldehydo (formyl) derivatives of said sulfonic acids, sulfonamides and sulfonimides, and beta unsaturated alkene sulfonic acids having 4 to 2 carbon atoms.

4. A method for electrodepositing bright nickel which comprises the steps of electrolyzing an aqueous acidic solution of at least one nickel salt selected from the group consisting of nickel sulfate, nickel chloride, nickel fluoborate and nickel sulfamate, said bath also containing dissolved therein about 0.005 to about 2 grams/liter of at least one alkynoxy alkane carboxylic acid having a total of 5 to 15 carbon atoms in which the unsaturated triple bonded carbon to carbon linkage is separated from the carboxyl group by 2 to 4 inclusive carbon atoms and 1 intermediate oxygen atom, and containing the grouping,

in which R is selected from the group consisting of-hydrogen, methyl, carboxyl and carboxymethyl radicals, R1 is selected.,fro'm' the group consisting of hydrogen and methyl radicals, R2 is selected from the group consisting of hydrogen, methyl and ethyl radicals, and n is not greater than 1 and in conjunction therewith about 0.1 gram/liter to. saturation of at least one brightener selected from the group consisting of benzene, diphenyl andnaphthalene sulfonic acids, benzene sulfonamides and sulfonimides and di-benzene sulfonamides and sulfonimides and the halogenic, methyl, aldehydo derivatives of said sulfonic acids, sulfonamides and sulfonimides, and beta. unsaturated alkene sulfonic acids having 4 to 2 carbon atoms.

5. A method in accordance with claim 4 wherein said carboxylic acid is 2-butynoxy-l,4-diacetic acid (HOOC. CH2OCH2CECCH2OCH2COOH) and is present in a concentration of 0.04-l.5 gram/liter.

6. A method in accordance with claim 4 wherein said carboxylic acid is 2-propynoxy-1-acetic acid (HCEC CHzOCHzCOOH) and is present in a concentration of 0.005 to 0.15 gram/liter.

7. A method in accordance with claim 4 wherein said carboxylic acid is propynoxy propionic acid (HCEC- CH2OCzI-I4COOH) and is present in a concentration of 000540.15, gram/liter.

8. A method in accordance with claim 4 wherein said carboxylic acid is 1,l-dimethyl-2-propynoxy-l-acetic acid (HCEC'C(CH3)2OCH2COOH) and is present in a concentration of 0.01 to 0.2 gram/liter.

9. A method in accordance with'claim 4 wherein said carboxylic acid is butynoxy 1,4 -dipropionic acid (HOOC-C2H4OCH2CEC--CH2OC2H4COOH) and is present in a concentration of 0.03 to 2.0 grams/liter.

10. A bath for electrodepositing bright nickel in accordance with claim 1 and having dissolved therein propynoxy acetic acid (HCECCH2OCH2--COOH) in a concentration of 0.005 to 0.15 gram/liter.

11. A bath for electrodepositing bright nickel in accordance with claim 1 and having dissolved therein 1,1-dimethyl-Z-propynoxy-l-acetic acid (HCECC(CH3)2 OCHZCOOH) in a concentration of 0.01 to 0.2 gram/ liter.

12. A bath for electrodepositing bright nickel in accordance with claim 1 and having dissolved therein propynoxy propionic acid (HCECCH2OC2H4 COOH) in a concentration of 0.005 to 0.15 gram/liter.

13. A bath for electrodepositiong bright nickel in accordance with claim 1 and having dissolved therein 2-butynoxy-1,4-diacetic acid (HOOC-CH2OCH2C:: CCH2OCH2COOH) in a concentration of 0.04 to 1.5 gram/liter.

14. A bath for electrodepositing bright nickel in accordance with claim 1 and having dissolved therein butynoXy-l,4-dipropionic acid in a concentration of 0.03 to 2.0 gram/liter.

References Cited in the file of this patent UNITED STATES PATENTS 2,712,522 Kardos et al. July 5, 1955 

1. A BATH FOR ELECTRODEPOSITING BRIGHT NECKLE COMPRISING AN AQUEOUS ACID SOLUTION OF AT LEAST ONE NICKLE SALT SELECTED FROM THE GROUP CONSISTING OF NICKLE SULFATE, NICKLE CHLORIDE, NICKLE FLUOBORATE AND NICKLE SULFAMATE, SAID BATH ALSO CONTAINING DISSOLVED THEREIN ABOUT 0.005 TO ABOUTT 2 GRAMS/LITER OF AT LEAST ONE ALKYNOXY ALKANE CARBOXYLIC ACID HAVING A TOTAL OF 5 TO 15 CARBON ATOMS IN WHICH THE UNSATURATED TRIPPLE BONDED CORBAN TO CORBAN LINKAGE IS SEPERATED FROM THE CARBOXYL GROUP BY 2 TO 4 INCLUSIVE CARBON ATOMS AND 1 INTERMEDIATE OXYGEN ATOM, AND CONTAINING THE GROUPING, 